So you feel that the suffering of people being referred to as cis, is equivalent to the bigotry and pain the N-Word carries for Black people. I'd say something about False Equivalence, but that term feels mild, sort of like describing the slaves brought to America as involuntary immigrants; no matter what way you put it, it's a gross understatement of the horrors they went through.

In any case, the way you can flat-out type "cis," but cannot type out the N-Word in its entirety, does convey that one term is seen as a far greater slur than the other.

Contrary to your beliefs, cis isn't a term solely for straight people. Cis is the counterpart of trans. If you identify as the gender chosen for you, you are cis. Cis and trans are referring to gender identity, while Hetero or LGBT refers to sexual attraction. A Straight man can qualify as cis, but so can a Gay man. There is no slur about it.

In any case, given the many pejorative terms we've given Transgender individuals and the fact that Transgender people have the highest suicide rate of any group and are more likely to be the victim of a hate crime than any other minority group, I don't think them referring to us as cis is quite the crime against humanity you make it out to be. Due to persecution from cisgender society, a transgender person's life span averages out to be in the neighborhood of 30-35 years. So forgive me if I don't feel that being called cis is the worst possible offense ever.